This invention relates to excited frame vibratory conveying apparatus for conveying particulate material.
In most vibratory conveying systems, the vibratory drive is connected directly to the conveying frame or bed. Some experimentation has been conducted in which the vibratory device is connected to a support frame in which the support frame is excited or primarily vibrated with the vibration being transferred through springs indirectly to the conveying member or bed. Such systems have been referred to in the past as two mass, two spring vibratory conveyor systems or excited frame vibratory systems. Such past attempts have been described in the Long et al U.S. Pats. Nos. 2,876,891, and 2,951,581 granted Mar. 10, 1959 and Sept. 6, 1970 respectively. Additionally the Luger U.S. Pat. No. 3,380,572 granted Apr. 30, 1968 describes a similar system. The basic objective is to design such a system in which the vibration amplitude of the excited frame approaches zero while the conveyor bed or member is vibrated at its natural frequency of maximum amplitude. The principal variables are the rpm of the vibratory drive member, the spring constant of the support springs supporting the conveyor bed on the excited frame, the weight of the conveyor bed, the weight of the product or load being conveyed and the weight of the excited frame. The generally recognized advantages of such a system over conventional direct vibratory conveyors is that it is possible under some conditions to transfer less vibration into the floor or ceiling supports and to provide a conveyor that is considerably less massive than the direct drive vibrating systems.
However, one of the principal problems associated with excited frame vibratory conveyors involves vertical rocking of the conveying member and the transmission of substantial vertical forces into the stationary supporting structure. Long et al in U.S. Pat. No. 2,951,581 contends that such rocking problems may be solved by utilizing substantially vertical leaf or beam springs between the stationary supporting structure and the excited frame. Long et al contends that soft or coil springs that "float" the system are unsatisfactory and do not provide the proper vertical rigidity required to prevent rocking.
One of the principal objects and advantages of this invention is to provide a greatly improved excited frame, vibratory conveyor apparatus utilizing a "floating" suspension resilient support system in which the rocking or eccentric forces are greatly reduced.
A further object of this invention is to provide a greatly improved "excited frame" vibratory conveyor apparatus that is capable of operating over a rather large range of loading without adversely affecting its operation.
A further object of this invention is to provide an improved excited frame, vibratory conveying apparatus that is very simple in structure and economical in manufacture to enable the apparatus to enjoy a wide usage for conveying various particulate material.
These and other objects and advantages of this invention will become apparent upon reading the following detailed description of a preferred embodiment.